21100004542 has 4 divisors (see below), whose sum is σ = 31650006816. Its totient is φ = 10550002270.

The previous prime is 21100004483. The next prime is 21100004543. The reversal of 21100004542 is 24540000112.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100004543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5275001134 + ... + 5275001137.

It is an arithmetic number, because the mean of its divisors is an integer number (7912501704).

Almost surely, 2^21100004542 is an apocalyptic number.

21100004542 is a deficient number, since it is larger than the sum of its proper divisors (10550002274).

21100004542 is a wasteful number, since it uses less digits than its factorization.

21100004542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10550002273.

The product of its (nonzero) digits is 320, while the sum is 19.

Adding to 21100004542 its reverse (24540000112), we get a palindrome (45640004654).

The spelling of 21100004542 in words is "twenty-one billion, one hundred million, four thousand, five hundred forty-two".